Colored couplers



l atentecl Nov. 30, 194$ COLORED COUPLERS Dudley B. Glass, Paul W. Vittum, and Arnold Weissberger, Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application May 3, 1944, Serial No. 533,931

Claims. (Cl. 956) This invention relates to color photography and particularly to coupler compounds for use in photographic processes.

Color-forming compounds which react with the development product of aromatic amino developing agents to form colored images upon photographic development are Well known. Generally, these color-forming compounds or couplers are colorless or substantially colorless. This lack of color is usually desirable where the coupler is to be incorporatedin the emulsion layer and the unused coupler remains after formation of the colored image. When the coupler is used in the developing solution, it ma be colored without detriment to the final image, and some colored couplers are known, such as paraphenylazo acetoacetanilide which wasdisclosed in Mannes an Godowsky Patent 2,108,602.

We have now found a new type of coupler which may have applications in several fields. The new couplers are, in themselves, more or less strongly colored, and during the coupling reacfurther substituted. The aromatic or heterotion, the chromophore system in the coupler is broken up with the result that the original color of the coupler is destroyed and a new dye is formed. Thus, on developing an emulsion layer containing one of these colored couplers, the coupler color is destroyed, and a new color is formed by the coupling reaction, at those points where development occurs. There is formed in this way a dye image of one color on a background of another color.

It is, therefore, an object of the present invention to provide a colored coupler whose chromophore system is destroyed on coupling. A further object is to provide a novel radical replacement type of chemical reaction. A still further object is to provide color couplers suitable for color corwhere R is an aromatic or heterocyclic radical, especially an aromatic radical of the benzene series. Either the phenol nucleus or the aromatic or heterocyclic radical may contain other substltuents. For example, the phenol radical may have a fused-on benzene ring which may be cyclic radical (R in the general formula) may contain substituents; such as alkyl, carboxylic acid, hydroxyl, sulfonic acid, sulfonamide, alkylamine, acylamine or alkoxy.

In previous descriptions of phenolic hydroxyl compounds for color photography, it has been assumed that the position para to the hydroxyl group must be unsubstituted or substituted with certain readily replaceable groups, such as halogen, in order for coupling with the developer to occur. We have found that the position para t0 the phenolic hydroxyl group may be substituted with an azo group and that this group is removable by the oxidized developer when the amsubstituted coupler is treated with the oxidized developer either. in aqueous solution or in the Thus the coupler photographic emulsion layer. may be converted to a coupled compound and the azo groupireadily removed from it by means of reaction with the oxidized] developing agent. This reaction appears to proceed as follows:

where R is the same as in the general formula above.

The following examples illustrate compounds which contain para-azo-substituted phenolic hydro'Xy groups according to the general formulas above and which may be used to produce colored images according to our invention:

4-(X-phenylazo)-l-napl1tliol X=H, OH, SOaH, SOzNHz, N(OH3)2, NH COOHa, OCHa, COOH 5-(5-carbcry-2-isopropyl-plienyl-azo)- S-hydroxyquinoline 4-(X-phenylazo)-5-p-toluene-si11fcnamido)-1- naphthol X=same as Example 1 CHzCHzCH stooges.

X=same as Example 1 2-a-(p-tert.-amylphenoxy) butyramido-4-(p-acetamidophenylazo)phenol HOQ :nO-SOmm NH-C o-on-ootnu z-a-(p tert-amylphenoxyl-butyramido-4g(p-sulfamylphenylazo)-5- C1 methylphenol 7. i

2-chloro-4-(2-bcnzothiazolylazo)-1-naphthol 1 NH to I 05 11 2-(p-tert.-amylbenzoylamino)-4-(Z-qulnolyl-azo)-5-methylphenol Our compounds may be incorporated in the.

photographic developing solution-or in the emulsion layer according to their intended use and diffusion characteristics. In -"the specific examples listed above, Nos. 4, 5, 6-,. and .8 are suitable for use in the'emulsion layer. When. incorporated in the emulsion layer, the compounds may be added directly to their silver halide emulsion as the sodium or other water-soluble salt or they may be incorporated in a coupler solvent as. de

' essary in order to keep the reaction temperature at-.0. 3 C. After standing for ten minutes, the

diazotized solution was added to a solution of 144 g. (01 mole) of a-naphthol in 160 cc. of water which contained g. (0.5 mole) of sodium hydroxide. Ice was added in order to keep the temperature below 5 C. After standing for two hours .at.5 0., the alkaline solution was acidified mine and-para-aminophenol.

witlrS'O cc. of concentrated hydrochloric acid. The azo compound was removed by filtration, washed with water and dried in air. The yield was quantitative. After recrystallizing from acetic acid; the product melted at 239240 0;

Our' compounds are particularly useful in a process, such as that of Hanson U. S. Patent $449,966, granted-September 21, 1948. TheI-Ianson process involves a color correction methodin which a colored coupler is incorporated in the photographic emulsion layer prior to exposureand upon development is converted into 'a colored imagewhere the layer was exposed. The coupler remaining in the unexposed portions of the layer retains its original color, and by suitable choice of thecolor of the original coupler and the color of the. final dye image, a masking or correction efiect. can be. obtained.

Various photographic developing agents can be employed with the couplers of our invention. The primary aromatic amino developing agents are. generally suitable including the phenylenediamines and aminophenols. The alkyl phenylenediamines may be substituted in the amino group as well as in the ring. Suitable compounds are diethylparaphenylenediamine, monomethyl'paraphenylenediamine, dimethyl paraphenylenedia- These compounds are. usually employed in the salt form, such as the hydrochloride or the sulphate whichare more stable than the free amines. All of' these compounds have a primary amino group which en- ;ables-the oxidation product of' the developer to couplewith'the color-forming compounds to form dye images.

The following developing solution is suitable for developing gelatino silver halide layers containing; colored couplers according to our invention.

2-amino-5-diethyl-amino toluene I-ICli ams" 2 Sodium sul'phitedo 2 Sodium carbonate do 20 Potassium bromide. do 2 Water to liter 1 where R isan aromatic nucleus selected from the: class consisting. of. nuclei of the benzene and naphthalene series, said nucleus having the azo' group and the hydroxyl group para to each other,

and R is selected from the class consisting of aromatic and heterocyclic radicals, and said coupler compound contains no reactive phenolic hydroxyl group other than that to which the azo group is attached exposing said layer and developing it with a primary aromatic amino developing agent, thereby splitting off the --N=N-R group in said coupler compound and coupling said compound at the point of splitting with the oxidation product of the primary aromatic amino developing agent to form a dye image, leaving said coupler compound intact in the regions of said layer undeveloped by said developing agent.

2. The method of developing a colored image in a silver halide emulsion layer, which comprises incorporating in said layer a coupler compound having the formula: 1

where R is a naphthalene nucleus, said nucleus having the azo group and the hydroxyl para to each other, and R is selected from the class consisting of aromatic and heterocyclic radicals, and said coupler compound contains no reactive phenolic hydroxyl group other than that to which the azo group is attached, exposing said layer and developing it with a primary aromatic amino developing agent, thereby splitting off the group in said coupler compound and coupling said compound at the point of splitting with the oxidation product of the primary aromatic amino developing agent to form a dye image, leaving said coupler compound intact in the regions of said layer undeveloped by said developing agent.

3. The method of developing a colored image in a silver halide emulsion layer, which comprises incorporating in said layer a coupler compound having the formula:

where X is selected from the class consisting of hydrogen, hydroxyl, sulfonic acid, sulfonamido, dialkylamino, and acetylamino groups, and said coupler compound contains no reactive phenolic hydroxyl group other than that to which the azo group is attached, exposing said layer and developing it with a primary aromatic amino developing agent, thereby splitting off the group in said coupler compound and coupling said compound at the point of splitting with the oxidation product of the primary aromatic amino developing agent to form a dye image, leaving said coupler compound intact in the regions of said layer undeveloped by said developing agent.

4. The method of developing a colored image in a silver halide emulsion layer, which comprises incorporating in said layer a coupler compound having the formula:

where R is selected from class consisting of aromatic and heterocyclic radicals, and said coupler compound contains no reactive phenolic hydroxyl group other than that to which the azo group is attached, exposing said layer and developing it with a primary aromatic amino developing agent, thereby splitting off the --N=NR group in said coupler'compound and coupling said compound at the point of splitting with the oxidation product of the primary aromatic amino developing agent to form a dye image, leaving said coupler compound intact in the regions of said layer undeveloped by said developing agent.

5. The method of developing a colored image in a silver halide emulsion layer, which comprises incorporating in said layer a coupler compound having the formula:

exposing said layer and developing it with a primary aromatic amino developing agent, thereby splitting off the group in said coupler compound and coupling said compound at the point of splitting with the oxidation product of the primary aromatic amino developing agent to form a dye image, leaving said coupler compound intact in the regions of said layer undeveloped by said developing agent.

DUDLEY B. GLASS.

PAUL W. VITTUM.

ARNOLD WEISSBERGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,102,028 Fischer June 30, 1914 2,092,425 Ullman et al. Sept. 7, 1937 2,107,941 Hess et a1. Feb. 8, 1938 2,108,602 Mannes et al. Feb. 15, 1938 2,135,366 Tinker Nov. 1, 1938 2,182,814 Marasco Dec. 12, 1939 2,189,817 Morris Feb. 13, 1940 2,220,123 Schwarc Nov. 5, 1940 2,227,981 Schinze1 Jan. 7, 1941 2,263,012 Schinzel Nov. 18, 1941 2,271,230 Peterson et a1 Jan. 27, 1942 2,295,008 Porter et a1. Sept. 8, 1942 2,295,009 Porter et al Sept. 8, 1942 2,297,732 Woodward Oct. 6, 1942 2,299,641 Middleton et a1. Oct. 20, 1942 2,304,820 Hanford et a1. Dec. 15, 1942 2,308,023 Peterson Jan. 12, 1943 2,322,006 Fierke et al June 15, 1943 2,330,291 Kirby Sept. 28, 1943 2,367,531 Salminen Jan. 16, 1945 FOREIGN PATENTS Number Country Date 503,752 Great Britain Apr. 11, 1939 503,824 Great Britain Apr. 11, 1939 

